The present invention relates generally to manufacturing composites, and more particularly to a method for detecting misalignment of composite fiber filaments during, and due to, processing (i.e., manufacturing) of the composite.
A "composite" is defined to be a material having any (metal or non-metal) fiber filament embedded in any (metal or non-metal) matrix binder. The term "metal" includes an alloy. An example of a composite is a material having graphite filaments embedded in an epoxy matrix binder. Because of their light weight and great strength, composites are being considered for use in diverse applications, such as in aircraft engine fan blades.
For critical structural applications of composites, the presence of defects, even in small amounts, is detrimental to the mechanical performance of the composites. Misalignment of initially-precisely-aligned fibers within the matrix binder during subsequent processing of a composite (such as, for example, during a subsequent compression molding process) leads to a manufactured composite which can suffer from wrinkling, bending, buckling, porosity, delamination and the like. Conventional ultrasonic scanning or x-ray CT is effective at analyzing composites in the cured state but is not effective at analyzing composites during processing due to the presence of the forming apparatus (e.g., mold or autoclave) surrounding the composites during manufacture.
What is needed is a method for detecting fiber misalignment in a composite during, and due to, the composite manufacturing process which can be used to evaluate changes in manufacturing parameters (e.g., changes in compression-mold closing speed) which can lead to defect-free manufactured composites.